Wind force not affecting hair particles
Try changing the Initial Orientation under Rotation from  "Object Y" to "Velocity/Hair". 



Keep your other numbers as they are; those in this image are for my particle system.

This will probably mean that your wheat will not stand up right. To fix that, select "Rotation" in the Render section. Then, if the wheat is still not standing up, try rotating your actual "Bugray" object by 90 degrees along first the X, then Y then Z axes.



Each time come back to your main layer with the particle system on it to check the effect, then if the wheat is still not upright, undo the previous rotation and try a different axis. 

Eventually the wheat should stand up, and because it's rotation is following the hair, it should be affected by wind and other force fields.